car cigarette lighter watts??

i want to put an adapter that allows me to plug in outlets through the cigarette lighter in my car. If i used a (120 V~60Hz) 38W guitar amp (connect with the outlet adapter), would it kill my car battery (optima red top) or blow a fuse somewhere?

i want to put an adapter that allows me to plug in outlets through the cigarette lighter in my car. If i used a (120 V~60Hz) 38W guitar amp (connect with the outlet adapter), would it kill my car battery (optima red top) or blow a fuse somewhere?

They do make inverters that can handle this much power, they will need to be hard wired to your battery, and used with the car running. Nothing that plugs into a cigarette lighter will work... at least safely.

__________________
Democracy substitutes election by the incompetent many for appointment by the corrupt few. - George Bernard Shaw

While the amp is rated for 38W, I'm sure that the actual draw from the outlet is a hell of a lot more than the .3A posted above. Post the manufacturer and model # of the amp and I can do a bit of googling to find the technical specs for you. Something just doesn't seem right. I mean, my cell phone charger pulls .2 amps. No way that an amp is only drawing .3A.

for my CL the fuse is 10amp but that is 2 outlets so usable wattage is max 120W

This isn't a 12v device.

Quote:

Originally Posted by IslandSi

P (wattage) = I(amps) x E (voltage)

If you know any two of those you can figure out the 3rd. Just plug in numbers and use simple 4th grade algebra.

So why didn't you answer the question?

Quote:

Originally Posted by JDM_Ej

They do make inverters that can handle this much power, they will need to be hard wired to your battery

No

Quote:

Originally Posted by JDM_Ej

and used with the car running.

No

Quote:

Originally Posted by JDM_Ej

Nothing that plugs into a cigarette lighter will work... at least safely.

No

Quote:

Originally Posted by uses0ap

i want to put an adapter that allows me to plug in outlets through the cigarette lighter in my car. If i used a (120 V~60Hz) 38W guitar amp (connect with the outlet adapter), would it kill my car battery (optima red top) or blow a fuse somewhere?

While the amp is rated for 38W, I'm sure that the actual draw from the outlet is a hell of a lot more than the .3A posted above. Post the manufacturer and model # of the amp and I can do a bit of googling to find the technical specs for you. Something just doesn't seem right. I mean, my cell phone charger pulls .2 amps. No way that an amp is only drawing .3A.

That's because your phone is low voltage. If the amp was a 12v device, the current pull would be 3.17 A.

Quote:

Originally Posted by IslandSi

Nice ninja edit. But like I said in my above post, there's no way in hell an amplifier is only pulling a third of an amp.

You simply don't understand the direct relationship between voltage and current. But what do I know, I'm only an EE who designs and builds circuits all day every day.

You clearly, clearly don't. Otherwise you wouldn't be saying stupid stuff like this:

I guess the OP better halt his plans for his in-cabin studio then.

lol you're not the only one who has a EE degree and understands about designing circuits.........personally I would not be using a noisy Inverter to power an audio amp.......but hey what do I know.........lol

personally I would not be using a noisy Inverter to power an audio amp

Like I said, the OP had better cancel plans for his in-car recording studio. And everyone should probably throw away their tickets to his in-car performance this weekend.

Quote:

Originally Posted by YeuEmMaiMai

but hey what do I know.........lol

You know how to follow the GDD protocol:

1. Someone asks a question.
2. 9 people read the question and make worthless, un-helpful posts.
3. The 10th person answers the question.
4. Everyone else comes back to nitpick, split hairs, and post any extraneous info that is even remotely related to the topic in an attempt to seem useful, intelligent, or simply to "win."

Original questions:

Quote:

Originally Posted by uses0ap

would it kill my car battery

No

Quote:

Originally Posted by uses0ap

or blow a fuse somewhere?

No, although this would in fact be the worst case scenario if the amp draws too much current. Even shorting the circuit to ground won't burn the wires.

That's because your phone is low voltage. If the amp was a 12v device, the current pull would be 3.17 A.

You simply don't understand the direct relationship between voltage and current. But what do I know, I'm only an EE who designs and builds circuits all day every day.

A 38W amp is probably going to draw ALOT more than 3.17A at 12V. The power rating of an amp is typically the OUTPUT, and NOT the consumption. Typically, amps are somewhere around 50-60% efficient. So, in order to be conservative about how well this will all work, we should probably assume that this amp is going to draw TWICE the amount of power that its output is rated at (76W). This means that the amp would probably draw about 6.34A at 12V (most appliances actually list the amp draw at 120V somewhere - multiply this by a factor of 10). Of course, these inverters are not 100% efficient. But after using them for quite a few years, I have come to the conclusion that they are actually not too bad efficiency-wise (even if your typical cheapo inverter CAN'T produce a good sine wave) - probably around 90% efficient. This brings current draw up to around 7A, which is well below the 10-15A rating of a typical cigarette lighter fuse.

A couple more things. I should add that I have used cigarette lighter inverters to run MANY things that draw AT LEAST this much power from the lighter with no problems. Just be sure that you use an inverter with a large enough power rating. Those dinky little things that have the cigarette lighter plug AND inverter in the same case that put out ~30-40W will not work. I would recommend 100W or more. Also, if this is something you are REALLY serious about doing ALOT, I would consider having wires going directly to the battery to run your inverter. Perhaps you could have a second cigarette lighter under the dash for just this purpose. The issue here is the size of the wires that supply power to a typical cigarette lighter: they tend to be VERY small (around #18AWG). And because of this, voltage drop between the battery and lighter will be significant. This will cause your inverter to sound the alarm fairly quickly. 10AWG or 12AWG would be a better size to use. Of course, direct wiring has the disadvantage that, once you hear the alarm with THIS setup, your battery might be too discharged to start the car.

Quote:

Originally Posted by IslandSi

They also create a lot of NOISE since they're basically creating a fake alternating current. Probably not the best thing to use in sound producing equipment.

Cheap inverters typically produce a kind of square waveform called a 'modified sine wave'. Unlike a true square wave, the 'modified sine wave' stays at zero for a time between Vmax and -Vmax. This brings the waveform a LITTLE closer to a true sine wave (in terms of reduced harmonics). But it can still lead to noise. But the amount of noise that you are likely to hear from audio equipment all depends on the quality of the filtering in that equipment. So the noise can be VERY significant if filtering is not good. However, even if this is the case, it may only be noticeable when there is no signal.

1. Someone asks a question.
2. 9 people read the question and make worthless, un-helpful posts.
3. The 10th person answers the question.
4. Everyone else comes back to nitpick, split hairs, and post any extraneous info that is even remotely related to the topic in an attempt to seem useful, intelligent, or simply to "win."

X 10 Best Laugh I've had all Day

__________________
Diagnose, Diagnose, and PROVE IT.Then and only then replace the part.

Honda and the Honda marquee are registered trademarks of the American Honda Motor Company, Inc. Neither American Honda Motor Company nor its subsidiaries or affiliates shall bear any responsibility for Honda-Tech.com content, comments, or advertising. Honda-Tech.com is not affiliated with American Honda Motor Company in any way. American Honda Motor Company does not sponsor, support, or endorse Honda-Tech.com in any way.
Copyright/trademark/sales mark infringements are not intended or implied.